1. Field of the Invention
The present invention relates to a cloth inspecting device on a loom which detects abnormality of a cloth during weaving by detecting means provided with a light-receiving device that moves in the width direction of the cloth to receive light coming from the cloth within a region in the cloth moving path of the loom.
2. Description of the Prior Art
In separating a cloth inspecting step from a weaving step to determine the properness/improperness of a cloth, the decision about the properness/improperness of the cloth cannot be made unless the cloth weaving is completed. A loom is not equipped with a device to detect the improper insertion of warps between healds or reeds, or the lashing-in of warps due to entangling of upper and lower warps at the time of making an opening, if such occurs. Therefore, the operation of the loom continues in that state until weaving is complete, and this defect in the warp direction of the cloth remains until the completion of the weaving. Even if the woven cloth has no defect, it is necessary to put the cloth through a cloth inspecting step to check the properness/improperness, inevitably deteriorating the cloth inspecting efficiency.
Conventionally, a device shown in FIGS. 15 and 16 and a device shown in FIGS. 17 and 18 have been proposed as a cloth detecting device in a loom (Japanese Unexamined Patent Publication No. Hei 2-160957). In the device shown in FIGS. 15 and 16, a cylindrical reflector 62 equal in length to or longer than the weaving width of a cloth W is provided along the width of the cloth W directly below the cloth W between reeds 60 and an expansion bar 61. A rod-shaped convex lens 63 is fitted in a cutaway provided over the entire length of the reflector 62. The reflector 62 is so provided that the convex lens 63 faces upward. A rod-shaped light source 64 is retained in a hollow portion of the reflector 62. A line sensor 65 of nearly the same length as the convex lens 63 is provided in the direction of the weaving width, directly above the reflector 62 with the cloth W therebetween, and the light-receiving surface of the line sensor 65 faces downward. A cover 66 is provided at the back of the line sensor 65, with its lower edge 66a set at the position contacting the top surface of the cloth W. Emitted light converged in line by the convex lens 63 passes through the cloth W to be received by the line sensor 65. The output signal of the line sensor 65 is compared with a set value stored in a reference fabric memory to determine the properness/improperness of the cloth. In the device shown in FIGS. 17 and 18, a cover 68 is slidably supported on a pair of guide rails 67. A threaded drive shaft 69 is engaged with the cover 68, penetrating therethrough, and is the cover 68 reciprocated at a given period by a motor 70. Retained in the cover 68 is a light-emitting apparatus, which comprises a light source 71 and a convex lens 72, and a light-receiving apparatus, which comprises a light-receiving element 73 and a convex lens 74. These light-emitting and light-receiving apparatuses run and scan over the entire weaving width area of the cloth W in accordance with the reciprocation produced by the threaded drive shaft 69. The lower edge of the cover 68 is set apart from but in the vicinity of the top surface of the cloth W.
Considerable fiber dust fly or dust is drifting in a factory where a loom is placed, and will stick on a light-receiving device, causing noise on a detection signal from the light-receiving device, unless the light-receiving device is covered with a cover. In the device shown in FIGS. 15 and 16, the line sensor 65, which is the light-receiving device, is covered with the cover 66 and the lower edge 66a of the cover 66 is set in contact with the top surface of the cloth W, making it difficult for fly or dust to stick on the light-receiving device. At the time the lower edge 66a moves away from the top surface of the cloth W due to vibration of the cloth W, however, fly or dust may enter the cover 66. To prevent this, it can possibly be considered that the lower edge 66a is pressed against the top surface of the cloth W, which will however increase the frictional resistance to the lower edge 66a. Further, this device requires the line sensor 65 equal in length to or longer than the weaving width of the cloth W, raising a problem of increasing the manufacturing cost.
In the device shown in FIGS. 17 and 18, there is a clearance between the cover 68 which covers the light-emitting and light-receiving apparatuses and the top surface of the cloth W, so that fly or dust gets in the container portion of the light-emitting and light-receiving apparatuses, thus dropping the cloth inspecting precision. Further, fly or dust are deposited on the threaded drive shaft 69 that drives the cover 68, and obstructs the driving of the cover 68. Furthermore, the cover 68, which reciprocates in the width direction of the cloth W, may be collided with another object by an unexpected accident.
It is therefore an object of the present invention to provide a cloth inspecting device on a loom, which will surely protect detecting means that runs in the direction of the weaving width of a cloth during weaving to optically detect a defect of the cloth, allows the detecting means to smoothly run without being influenced by fly or dust, and surely prevents fly or dust from sticking on a light-receiving device to reduce fly- or dust-originated noise on a detection signal, thus ensuring cloth inspection with a smaller detection error.